If they get the likes of Kane or Tarasenko and proceed to sign them to lengthy deals, then this team will indeed become like a retirement home in years to come. There's already Lee at 32, Nelson 31, Cizikas 31, Bailey 33, Pageau 30, Martin 33 and Clutterbuck 34 with term beyond this season. I know it's easy to get rid of Martin and that both Bailey and Clutterbuck's deals will expire in 24, but they won't magically disappear. I also believe Lou will go to great lengths to re-sign both Varlamov and Mayfield, who at 34 and 31 are looking at multiyear deals as well.
None of the players above will be getting any better in subsequent years - they'll all start regressing on lucrative multiyear deals. Ideally, you'd want to move those players out in the next couple of years, not add more players their age (or older).
If they're looking to add, then go for someone who's best years will be as an Islander, not someone who's out to make one last buck in the twilight years of his career. If they think Kane wants to come here, play with Barzal and win - offer him two years as a UFA, because that is the current window the Islanders have - at most. Tarasenko the same.
Meier and Horvat fit the bill nicely and have their best years ahead. I'd much rather go for one of them.